19 research outputs found

    Understanding continent-wide variation in vulture ranging behavior to assess feasibility of Vulture Safe Zones in Africa: Challenges and possibilities

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    Protected areas are intended as tools in reducing threats to wildlife and preserving habitat for their long-term population persistence. Studies on ranging behavior provide insight into the utility of protected areas. Vultures are one of the fastest declining groups of birds globally and are popular subjects for telemetry studies, but continent-wide studies are lacking. To address how vultures use space and identify the areas and location of possible vulture safe zones, we assess home range size and their overlap with protected areas by species, age, breeding status, season, and region using a large continent-wide telemetry datasets that includes 163 individuals of three species of threatened Gyps vulture. Immature vultures of all three species had larger home ranges and used a greater area outside of protected areas than breeding and non-breeding adults. Cape vultures had the smallest home range sizes and the lowest level of overlap with protected areas. RĂĽppell\u27s vultures had larger home range sizes in the wet season, when poisoning may increase due to human-carnivore conflict. Overall, our study suggests challenges for the creation of Vulture Safe Zones to protect African vultures. At a minimum, areas of 24,000 km2 would be needed to protect the entire range of an adult African White-backed vulture and areas of more than 75,000 km2 for wider-ranging RĂĽppell\u27s vultures. Vulture Safe Zones in Africa would generally need to be larger than existing protected areas, which would require widespread conservation activities outside of protected areas to be successful

    Data from: Panmixia supports divergence with gene flow in Darwin’s small ground finch, Geospiza fuliginosa, on Santa Cruz, Galápagos Islands

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    The divergence-with-gene-flow model of speciation has a strong theoretical basis with a growing number of plausible examples in nature, but remains hotly debated. Darwin’s finches of the Galápagos Archipelago have played an important role in our understanding of speciation processes. Recent studies suggest that this group may also provide insights into speciation via divergence with gene flow. On the island of Santa Cruz, recent studies found evidence for adaptive divergence in Darwin’s small ground finch, Geospiza fuliginosa, between ecologically contrasting arid and humid zones. Despite the short geographical distance between these zones, strong disruptive selection during low rainfall periods is expected to generate and maintain adaptive divergence. Conversely, during high rainfall periods, when disruptive selection is predicted to be weakened, population divergence in adaptive traits is expected to break down. Because periods of low and high rainfall irregularly alternate, the geographical pattern of adaptive divergence can be assumed to break down and, importantly, regenerate in situ. Here, we use microsatellite allele frequency data to assess the genetic population structure of G. fuliginosa on Santa Cruz. We sample 21 sites and four ecological zones across the island. We reject hypotheses of population substructure linked to ecological and geographical differences among sites in favour of a single panmictic population. Panmixia implies high levels of gene flow within Santa Cruz, which favours selection over genetic drift as a valid process generating phenotypic divergence in G. fuliginosa on Santa Cruz. We discuss how our findings may support classic adaptation, phenotypic plasticity, matching habitat choice or any combination of these three processes

    Have population declines in Egyptian Vulture and Red-headed Vulture in India slowed since the 2006 ban on veterinary diclofenac?

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    Populations of three vulture species of the genus Gyps, the Egyptian Vulture Neophron percnopterus and Red-headed Vulture Sarcogyps calvus have declined markedly on the Indian subcontinent since the mid-1990s and all are now Critically Endangered or Endangered. Gyps vultures have been killed by the widely used non-steroidal anti-inflammatory drug diclofenac, ingested when they feed on carcasses of domesticated ungulates treated with the drug shortly before death. However, it is not known whether Egyptian Vulture and Red-headed Vulture are also sensitive to diclofenac. Veterinary use of diclofenac was banned in India in 2006. Since then, the prevalence and concentration of diclofenac in domesticated ungulates carcasses has decreased and population declines of Gyps vultures have slowed or reversed. Here, we examine counts of Egyptian and Red-headed Vultures obtained on road transects in and near protected areas between 1992 and 2011. We found indications that the declines in both species appear to have slowed and possibly increased after the ban was introduced, though the small numbers of birds counted make this conclusion less robust than that for the Gyps species. These results suggest that both species may have been adversely impacted by diclofenac and that government bans on this drug, which are beginning to take effect, may benefit a wider range of vulture species in the Indian subcontinent than was previously thought

    Population trends in Himalayan Griffon in Upper Mustang, Nepal, before and after the ban on diclofenac

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    The Upper Mustang region of Nepal holds important breeding populations of Himalayan Griffon Gyps himalayensis. Despite this species being considered 'Least Concern' on the IUCN Red List, the population in Upper Mustang had declined substantially in the early to mid-2000s. During that period, the non-steroidal anti-inflammatory drug diclofenac was commonly used to treat illness and injury in domesticated ungulates throughout Nepal. The timing and magnitude of declines in Himalayan Griffon in Upper Mustang resemble the declines in resident populations of the 'Critically Endangered' White-rumped Vulture Gyps bengalensis and Slender-billed Vulture Gyps tenuirostris in Nepal, both of which are also known to be highly sensitive to diclofenac. Since 2006, the veterinary use of diclofenac has been banned in Nepal to prevent further vulture declines. In this paper, we analyse the population trend in Himalayan Griffon in Upper Mustang between 2002 and 2014 and show a partial recovery. We conclude that the decline is now occurring at a slower rate than previously observed and immigration from areas where diclofenac was either not or rarely used the probable explanation for the recovery observed
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